30+ years ago we had a 2 storey extension built and a whole-house water
heating woodburner installed at the same time.
The chap that installed the woodburner and associated plumbing recommended a
curved radiator in a bay window. I took his advice. He toddled off with an
existing rad one day and returned the next with rad curved to exact profile.
Works perfectly to this day. Rad is single panel about 6ft x 2ft 6ins with a
relatively tight radius.
I asked how this was done- rolled to radius, seams rewelded and pressure
tested. Pretty good for an overnight job.

This Spring we will have our 30+ yo gas boiler replaced. Guy that's doing it
has recommended that some older rads be replaced, including the curved one,
as powerflushing might uncover some pinhole leaks. He doesn't know where to
get it replaced.

Any ideas please?

Many thanks,
Nick.